Don't know how you've found out that this variant of Sality is 3 years old as malware is being updated constantly to evade detection.

In the case of viruses infecting other computers via network it is necessary to find the source of infection. Perhaps somebody connected a notebook not running ESET and infected with a virus to your network. In that case, the virus would spread across the network but infected files should be detected and cleaned.

I'd suggest providing ESET with more details about the infection (SysInspector, Threat logs from affected computers) as well as a bunch of affected files that cannot be cleaned or are completely undetected and you deem them suspicious.

Hello lynjac
No vendor can offer 100 procent protection,... it would be nice wouldn't it .
Malware are easily changed/updated by the malware creator, you cannot expect 100 procent detection, that is why multi layered protection is necessary, but that you know of course . If you still have the malware sample please submit it, so we all can benefit of your discovery : http://kb.eset.com/esetkb/index?pag...earch&viewlocale=en_US&searchid=1315235154534

The Win32/Sality malware familiy is constantly being updated. It is likely you were infected by a variant which was detected by the old signature but is something newer. If you still have some infected files they can be submitted to ESET's virus lab for further analysis.